Hydrostatic car transmission

Lamont in NC · Dec 12, 2015

I was reading about CVT transmissions tonight with the belts and varying sized pulleys and I started to wonder why cars couldn't be made like tractors with hydrostatic transmissions. Frankly setting up a car like a tractor where you set the throttle to max power or best fuel economy rpm then managed vehicle acceleration and top speed with the hydro just like you do on a tractor would seem to make sense to me. I'm sure there's a reason or they'd be doing it.

David G · Dec 12, 2015

Hydrostatics have quite a bit of loss to them.

Brendon-KS · Dec 12, 2015

Hydrostatic drives are pretty bad when it comes to efficiently transmitting power. Consider that the hydraulic oil cooler on a large hydro drive machine such as a self-propelled windrower can dissipate nearly a quarter of the engine's power as heat - that heat represents fuel that is not used for doing work. Hydro drives are great for infinite speed control and easy direction changes but it comes at a cost. For an automobile this cost - the loss of efficiency - is far more than the benefit that you'd get.

Janicholson · Dec 12, 2015

Even CVT had to be engineered with serious differences between them and a snowmobile trans. Just to approximate the efficiency of gears. the engine speed and efficiency gain had to be enough to have an incremental gain on a stick shift. Jim

Goose · Dec 12, 2015

When my wife and I were married, she had a '61 Chevy with a transmission similar to a hydrostat. As I recall, they were called a "Turboglide". It didn't have distinct gears, just varied according to what was needed. Also had a 348 engine, the forerunner of the 409.

Chevy had a lot of problems with them. They couldn't handle the engine torque and they were pricey to fix or overhaul. One day, I shifted my wife's from Drive to Park and a knock started in the transmission about like a rod knock. I shifted back to Drive, then back to Park and the knock went away.

That was enough for us. We traded it off. I think Chevy marketed them for only a couple of years and stopped building them.

Janicholson · Dec 12, 2015

A Dynaflow (Buick) was a Torque converter variable drive. It had (in some iterations) 7 moving components in the torque converter. Not efficient, but oh so smooth till it failed. Jim

Goose · Dec 12, 2015

We used to call them "Dynaslow". A buddy of mine had one at the time.

We were in jet fighter planes in the Marine Corps at the time, and we used to joke about his car taking off from a dead stop like a fighter plane. You ran the engine up to 100% power and got off the brakes.

Jon Hagen · Dec 12, 2015

Several of the hybrid cars use electric / mechanical IVT transmissions.
Not only are they stepless from start to top speed, they are very efficient and reliable, allowing for regenerative braking and keep the engine in its most efficient rpm range. My last two cars, a 50 mpg Toyota Prius and now, a 40 mpg Lincoln MKZ hybrid use them.

David G · Dec 12, 2015

A famous saying from those days. "Slip and slide with power glide"

Old weldor · Dec 12, 2015

Chevy actually had that turboglide available from 57-61. My brother had a 57 with the turbglide. They had a grade retard range instead of low.

CenTex Farmall · Dec 12, 2015

The Chevy Volt is principally similar in that the gas engine runs constant speed while the traction motor is variable. Excess current goes to the batteries till charged instead of needing to be dissipated.

Sprint 6 · Dec 12, 2015

Not entirely true. The Volt runs on pure battery until they get too low, then the engine starts in order to supplement battery current. The engine never charges the battery on a Volt. Seems counter intuitive, but that's the way it is. Volt batteries are only charged by regenerative braking and the charger socket.

CenTex Farmall · Dec 13, 2015

Well after some more digging, you are correct. I can see the logic though, gasoline power to charge the batteries would be expensive compared to grid power, also not much engine there to begin with to have to divide between charging the batteries AND propelling the car.
So when the batteries get to the cutoff point it goes pure locomotive.

Russ from MN · Dec 13, 2015

Hydrostatic drives are very inefficient, it would give you poor mileage, and the goal now is for better. We have a 2015 Subaru with the CVT which is very efficient and reliable.

Brendon-KS · Dec 13, 2015

The reason the Volt does this is that if the batteries were fully recharged by the gas engine it would defeat the purpose of having a plug-in electric car in the first place - to get the maximum amount of energy from the grid instead of from a gas tank.

MarkB_MI · Dec 13, 2015

Automatic transmissions and hyrostats have different applications. Hydrostatic transmissions are great when the demand for power is fairly constant, and there's not a lot of variation in speed. Open the throttle wide, pick the speed and go. An automotive transmission has to respond to much wider variations of power and speed. And it needs to respond almost instantly when there's a demand for power. Think about when you speed up to pass another vehicle: You need to simultaneously go to full throttle and downshift to a lower gear. An automotive automatic transmission will shift to the appropriate gear when more power is needed, and the driver just has to deal with one power control, the accelerator pedal. Now think about doing it with a hydrostat: You have to simultaneously open the throttle and reduce the transmission speed control, then increase the speed control as the vehicle accelerates. It's the same as you would do with a manual transmission, except you have to adjust the speed control constantly with a hydrostat rather than just make a couple of gear changes with the manual.

Modern automatic transmissions are ridiculously efficient. With as many as eight speeds plus torque converter lockup, they give up very little in efficiency to continuously variable transmissions, which is why CVTs haven't really taken off.

MarkB_MI · Dec 13, 2015

>The Volt runs on pure battery until they get too low, then the engine starts in order to supplement battery current. The engine never charges the battery on a Volt. Seems counter intuitive, but that's the way it is. Volt batteries are only charged by regenerative braking and the charger socket.

Not quite true. The internal combustion engine of the Volt is used to recharge the batteries as well as to directly drive the wheels, depending on conditions.

DLMKA · Dec 13, 2015

The real cat's meow would be a small diesel with a generator hanging on the back of the flywheel housing. Have proper electronics to run a traction motor on 2 or 4 wheels. Engine runs at most efficient speed and just vary fueling for power need. No batteries for storage, adds weight and cost and most lithium comes from conflict areas and China anyway. Maybe a small battery to act as a capacitor for regenerative braking to assist the engine for load transients. Would be very similar to a locomotive.

Plug-in cars are fine for people in cities that rarely travel more than 10-20 miles but people living in the country need an engine.

Sprint 6 · Dec 13, 2015

The Volt engine does not charge the batteries. GM did take some flack that the engine can be coupled to the trans at high speeds, making it not truly an "electric" car. But then again, did you expect Government Motors to tell the truth? The Volt is a tax money wasting experiment that would not have seen the light of day had the Government not seized control of GM.

John B. · Dec 13, 2015

Tractors use 80% of their power 80% of the time... Cars use 80% of their power only 20% of the time...

Working a tractor in the field you can operate at a constant speed but a car on the highway the speed is a constant variable.

Donald Lehman · Dec 13, 2015

I would think gas mileage would be horrible with a hydrostatic trans mission.

Dean · Dec 13, 2015

MUCH too inefficient (and expensive) for automotive use. Too much power is converted into heat.

You do not see hydrostatic transmissions in high HP tillage tractors for the same reason.

In the late 1950s-1960s, MAN tried to market hydrostatic railroad locomotives in the US. Their effort was a colossal failure due to the inefficiency of the transmission.

Dean

Dean · Dec 13, 2015

The Chevrolet Turboglide was marketed in the 58-61 model years. It was, indeed, a commercial failure as it was considerably more expensive than the Powerglide and few customers bought it.

Dean

Dean · Dec 13, 2015

Agreed, Mark. The once substantial efficiency differential between manual automotive transmissions and automatic transmissions of similar era are now vanishingly small.

Eventually, I expect automobiles, heavy trucks, farm tractors, etc., will have electronic transmissions.

GM developed a motor scraper (pan) with an electrical (not electronic) transmission in the 1960s but it was not marketed. Rather than front and rear engines as other self loading motor scrapers used at the time, The prototype had a single Detroit diesel 6V (8V?) 71 in the front driving a generator or alternator (can't remember) and electric motors were used on each wheel. The electrical transmission was similar to that used in railroad locomotives at the time. The electrical system was developed by Delco Products in Dayton, OH. The Euclid division developed the rest of the scraper.

The design was successful but it was not marketed due to changing economic conditions.

Dean

MarkB_MI · Dec 13, 2015

>GM developed a motor scraper (pan) with an electrical (not electronic) transmission in the 1960s but it was not marketed.

Not familiar with that one. My dad had a Euclid (Terex) TTS-14 twin-bowl scraper. Three 4-71 Detroits driving six-speed Allison automatic transmissions. About seventy feet long. Quite impressive.

Letourneau made some paddle-wagon scrapers that used large electric motors for steering and elevator power. They had manual transmissions for propulsion. We had a Model C Tournapull, which was quite troublesome to keep running.

buickanddeere · Dec 13, 2015

That is why there are 6 speed manuals and 6 to 9 speed automatics. Direct drive has the fewest losses.

buickanddeere · Dec 13, 2015

It's also why the Chevy Colt freaks out it's drivers when the ICE fires up to charge the batteries. The engine goes to full load at full rpms even though the car is at low speeds or sitting still.

Jiles · Dec 13, 2015

(quoted from post at 14:55:51 12/13/15) The Volt engine does not charge the batteries. GM did take some flack that the engine can be coupled to the trans at high speeds, making it not truly an "electric" car. But then again, did you expect Government Motors to tell the truth? The Volt is a tax money wasting experiment that would not have seen the light of day had the Government not seized control of GM.

Government Motors has a Long history of developing vehicles---and components--- and letting the consumer test them out.

jacksun65 · Dec 13, 2015

I had a Dodge pickup with an IVT trans worked great except turning going up hill it would bog and then take off spinning the wheels

GVSII · Dec 13, 2015

(quoted from post at 20:35:26 12/12/15) A Dynaflow (Buick) was a Torque converter variable drive. It had (in some iterations) 7 moving components in the torque converter. Not efficient, but oh so smooth till it failed. Jim

Had a friend who had a dynaflow buick.It would do 55 or 60 in neutral!

Dean · Dec 13, 2015

Remember, the Dynaflow was developed by Buick for use in upscale cars at a time, after WWII, when few if any of their buyers cared about fuel economy. What they did care about was quietness (Buick developed hydraulic valve lifters), smoothness (non shifting Dynaflow), ride quality (coil spring rear suspension), etc.

FWIW, the Dynaflow did have a low range but it was selectable only by manually shifting the selector into L. The Dynaflow did not shift between low range and high range. Rather the variable pitch torque converter continually adjusted as road speed increased. The Dynaflow was, in effect, a CVT, albeit a rather inefficient version.

The Dynaflow was produced for over 15 years making it, along with the Powerglide, TH 400 and Torqueflite, one of the most successful automatic automotive transmissions.

Dean

Dean · Dec 13, 2015

Fascinating, Mark.

I never saw such a machine but have seen many Euclid/Terex self loading scrapers. All of those that I saw were powered by 4 cylinder Detroits. Though not certain, I believe that they used single 471s in front and single 453s in back. Of course, both used Allison automatic transmissions with varialbe pitch torque converters. These machines were light years ahead of scrapers produced by Cat and others at the time.

Did your father's scraper use twin 471s in front to allow steering by adjusting the throttle of each engine? I do know that Euclid produced large bull dozers in the 50s and 60s that used twin 471s to allow steering without declutching either side by differential engine RPM. These machines, though more expensive, were also light years ahead of bull dozers offered by other manufacturers at the time.

The GM effort to produce a scraper (bull dozers were also anticipated) with diesel/electric power was intended to reduce manufacturing and maintenance costs by eliminating the second/third engine, transmission, etc. The project was shelved in the late 60s/early 70s due to the largely completed interstate highway project and resulting diminishing demand for such machines.

I believe that the efficiency improvements offered by electronic transmissions will eventually result in the application of such transmissions in virtually all markets, including farm tractors.

Dean

MarkB_MI · Dec 13, 2015

Dean, as I recall the single bowl TS-14 used a 6-71 in front and 4-71 in the rear. The tandem TTS-14 was basically a TS-14 with an extra bowl towed behind the first bowl. Each bowl had a rear-mounted engine and drive train. Steering, as with most scrapers, was accomplished by articulating the gooseneck between the tractor and front scraper. The rear scraper had no steering, so backing up was to be avoided. The throttle to the front engine was mechanical, while the two rear engines were controlled by an air-activated servo. So the rear engines were always either WOT or at idle. The transmissions were also air-controlled.

The beauty of the tandem scraper was its ability to self-load in all but the hardest soils. No need for a push cat. You loaded one bowl at a time, which meant the wheels on the other bowl always had traction. The main disadvantage was its length, but for our work we always had plenty of room to work. It was a little tricky maintaining the cut depth with the rear bowl; you just had a couple of pointers mounted to the bowl and gooseneck to give you a rough idea how deep you were cutting.

There are a couple of good pictures of a TTS-14 towards the bottom of the message thread below.
TTS 14 on heavyequipmentforums.com

MarkB_MI · Dec 13, 2015

>The Volt engine does not charge the batteries. GM did take some flack that the engine can be coupled to the trans at high speeds, making it not truly an "electric" car. But then again, did you expect Government Motors to tell the truth? The Volt is a tax money wasting experiment that would not have seen the light of day had the Government not seized control of GM.

Where do you get your information that the Volt can't charge its own batteries off its gas engine? It's easy enough to find information to the contrary. For example <a href="https://en.wikipedia.org/wiki/Chevrolet_Volt#Drivetrain">https://en.wikipedia.org/wiki/Chevrolet_Volt#Drivetrain</a> or <a href="http://gm-volt.com/chevy-volt-faqs/">http://gm-volt.com/chevy-volt-faqs/</a>

The latter link contains this simple explanation:

"The Volt is a series vehicle meaning only the electric motor powers the car at all times, the gas engine is just a generator for making electricity once the battery is depleted. A little like the Prius, the engine does help spin the wheels after the battery is depleted. GM engineers chose to do this because it improved efficiency by 10 to 15 percent."

Yes, it's true the Volt would never have gone into production without the GM bailout, for the obvious reason that General Motors would no longer exist to produce the Volt or any other car. Given that the E-Flex platform was in development the better part of a decade before the GM bankruptcy, it is a bad assumption to think the Volt was a government mandate.

keh · Dec 13, 2015

I had a 1955 Buick Special with Dynaflow for several years. It gave no trouble. For the time and the car weight(4000 pounds) it gave good fuel economy, 17.5 mpg. My impression was it effectively had a 2 speed transmission. I didn't notice any slippage but never towed anything with it. From discussions on here I have the impression that hydrostatic drives don't work well in tractors doing tillage.

KEH

Jiles · Dec 13, 2015

(quoted from post at 01:47:13 12/14/15)
I had a 1955 Buick Special with Dynaflow for several years. It gave no trouble. For the time and the car weight(4000 pounds) it gave good fuel economy, 17.5 mpg. My impression was it effectively had a 2 speed transmission. I didn't notice any slippage but never towed anything with it. From discussions on here I have the impression that hydrostatic drives don't work well in tractors doing tillage.

KEH

You are correct in that it was a two speed. Just couldn't feel the shift. Back in the day, I rebuilt MANY.
Sometimes, after a rebuild, it wouldn't shift--you knew it was a two speed then!

Sprint 6 · Dec 13, 2015

That article does not say the engine charges the battery, only excess energy goes to the batteries, if there is any left over. Energy usage in a Volt is so tightly controlled, it is unlikely there would be excess energy. If you drive a Volt until the battery is dead, then run till the full fuel tank is empty, the battery is still dead. The only way to meaningfully charge the battery is the charge port.

w1ebb · Dec 13, 2015

No such thing as a "Perpetual Motion Machine." Electric machine charging its own drive batteries........

Now when engines are built that propel vehicles using light energy like the Starship Enterprise.......

Hey, its possible!

We have the communicators...cellphones.

Phasers (set on "stun").... Stunguns and Tazers.

Shuttlecraft....Space Shuttles.

More power, Scotty!

LOL!! ROFLMFLAO!!!!

Even the "Federation of Planets" didn't have
"Perpetual Motion Machines!"

Scott

Hydrostatic car transmission

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Similar threads